The City Montessori School (CMS) in Lucknow, India, has retained its title as the world’s biggest brick-and-mortar school, says the Guinness Book of World Records.

At the start of the 2015 academic year, the school enrolled more than 50 000 pupils. They are taught in 1 000 classrooms by 2 500 teachers.

The school – its home city is the capital of India’s most populous state, Uttar Pradesh – is also over half a century old. It was started by a couple who had just over US$5 and five students needing schooling. Today, CMS is consistently ranked in the top 20 of India’s most respected schools.

Students wear identical uniforms, but will never meet all their classmates, as there is no one space big enough for assemblies. Classes on 20 campuses house on average 45 students per lesson; primary students pay a monthly fee of US$18 and their older counterparts US$47 per month. The school does not receive government funding and its fees are considered high.

Despite its size and best efforts, CMS is not able to reverse the dismally low literacy rate in Uttar Pradesh. On other levels, CMS is a resounding success: in 2002, it received the United Nations Educational, Scientific and Cultural Organization’s (UNESCO) Prize for Peace Education. More recently, the Dalai Lama conferred his Hope for Humanity award on the school’s founders.